Description

Extended attributes are
name:value
pairs associated with inodes (files, directories, symbolic links, etc.).
They are extensions to the normal attributes which are associated
with all inodes in the system (i.e., the
stat(2)
data).
A complete overview of extended attributes concepts can be found in
attr(5).

setxattr()
sets the
value
of the extended attribute identified by
name
and associated with the given
path
in the filesystem.
The
size
argument specifies the size (in bytes) of
value;
a zero-length value is permitted.

lsetxattr()
is identical to
setxattr(),
except in the case of a symbolic link, where the extended attribute is
set on the link itself, not the file that it refers to.

fsetxattr()
is identical to
setxattr(),
only the extended attribute is set on the open file referred to by
fd
(as returned by
open(2))
in place of
path.

An extended attribute name is a null-terminated string.
The
name
includes a namespace prefix; there may be several, disjoint
namespaces associated with an individual inode.
The
value
of an extended attribute is a chunk of arbitrary textual or
binary data of specified length.

By default
(i.e.,
flags
is zero),
the extended attribute will be created if it does not exist,
or the value will be replaced if the attribute already exists.
To modify these semantics, one of the following values can be specified in
flags:

XATTR_CREATE

Perform a pure create, which fails if the named attribute exists already.

XATTR_REPLACE

Perform a pure replace operation,
which fails if the named attribute does not already exist.

Return Value

On success, zero is returned.
On failure, -1 is returned and
errno
is set appropriately.

Errors

EDQUOT

Disk quota limits meant that
there is insufficient space remaining to store the extended attribute.

EEXIST

XATTR_CREATE
was specified, and the attribute exists already.

ENOATTR

XATTR_REPLACE
was specified, and the attribute does not exist.
(ENOATTR
is defined to be a synonym for
ENODATA
in
<attr/xattr.h>.)

ENOSPC

There is insufficient space remaining to store the extended attribute.

ENOTSUP

The namespace prefix of
name
is not valid.

ENOTSUP

Extended attributes are not supported by the filesystem, or are disabled,

Conforming To

See Also

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License & Copyright

Copyright (C) Andreas Gruenbacher, February 2001
Copyright (C) Silicon Graphics Inc, September 2001
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